[ARC5] BIG Variacs and popping breakers.

[Arden Allen]

> ......Well, it depends on just how "good" they are. The problem with 
> really good ones is that
there is no back-emf from the core without a load. Therefore, they show a 
dead-short to the
power line until they get "saturated" or whatever it is that is called when 
the magnetic field
builds up.  .........

The word "reluctance" comes to mind.  At zero winding current the magnetic 
domains are not aligned so inductive reactance is substantially zero.  Once 
the core is biased the domains are kept in order by the current flow.  Same 
principle as the bias needed for a magnetic tape recorder head.  Disclaimer: 
I'm not a magnetics expert so I'm just guessing.

Arden Allen
KB6NAX

He who is cruel to animals becomes
hard also in his dealings with men.
We can judge the heart of a man by
his treatment of animals.
—Immanuel Kant